U.S. Pat. No. 4,561,181 discloses a guide bar of this kind for portable handheld motor-driven chain saws and for work machines such as so-called wood harvesting machines or processors. The nose assembly section for the saw chain defines the forward end of the guide bar and is subjected to large loads during operation. Accordingly, bending forces must be taken up by the guide bar and these forces occur especially during tilting of the forward end. Pressure forces acting on the forward end of the guide bar during plunge-cutting operations and the dynamic directional-change forces of the rapidly moving saw chain are also considerable.
For the above reasons, the nose assembly section defining the forward end of the guide bar becomes worn substantially earlier than the base body section of the guide bar. In known guide bars, the nose assembly section is configured as a separate exchangeable component in order that the entire guide bar need not be discarded after the nose assembly becomes worn. Rivets or other releasable fastening elements which must be destroyed to be removed are used to attach the nose assembly section to the base body section. Accordingly, special tools must be used to destroy the fastening elements when exchanging the nose assembly section and to attach the replacement nose assembly section. This type of retrofit work cannot be carried out by the worker in the forest who is operating the tool or if so, only with a great deal of difficulty. A further disadvantage is seen in that the operator cannot tighten the guide bar connection at the location of use when this connection becomes loose as a consequence of the dynamic forces acting on the guide bar base body section and especially on the nose assembly section.